Refrigerating system



April 23, 1929. w. DUNKl-:RLEY

REFRIGERATING SYSTEM Filed April 13, 1927 Patented Apr. 23, 1929.

1,710,300l "UNITED STATES PATENT OFFICE.

WILLIAM DUNKERLEY, O1? NORTH MELBOURNE, VICTORIA, AUSTRALIA.

REFRIGERATING SYSTEM.

Application ledApril" 13, 1927, Serial No. 183,540, and in Australia February 24, 1927.

This invention relates to refrigerating systems and is applicable to such systems or installations operating either by compression or absorption.

The primary object of the invention is to provide improvements in refrigerating systems or installations whereby the normal cooling capacity of the system may be augmented to thereby enable a larger volume of )vork to be effected at the normal refrigerating temperature, or to lower the refrigerating temperature either uniformly throughout the system, or in any desired cooling zone or section thereof.

The' foregoing object is attained by incorporating in the system a booster or auxiliary compressor of the rotary type whereby the gaseous cooling agent from the expansion or cooling coils of the system may, instead of passing directly through the main suction pipe to the means for putting it under higher pressure as is usual, be diverted through a' by-pass or auxiliary circuit in which said auxiliary compressor is connected, and discharged from the latter into the main pressure-increasing means. In this manner, the normal suction pressure to which the gaseous cooling agent in any or all of the expansion coils or cooling sections of the system is subjected, may be supplemented by the suction developed in the auxiliary circuit, the resultant reduction in the lsuction pressure having the effect of intensifying the refrigerating action of the cooling agent.

The practical application of the invention to a refrigerating system permits of a greater output at the normal working temperature of the system, or alternatively the additional refrigerating effect due to the action of the auxiliary compressor any desired cooling section or sections without aecting the temperature obtaining in the other section or sections. Thus a relatively'low suction p1essu1'e'-may be maintained in any of the expansion coils or cooling sections without requiring such a low suction pressure throughout the system and thus calling for a main compressor of greater capacity and cost.

The auxiliary compressor may be readily incorporated in any existing refrigerating system without interfering with the latter except as may be required to connect piping which leads fromthe auxiliary compressor to the expansion coils or the main suction pipe of the system. Furthermore, owing to may be concentrated in i )tinct economical advantages.

Referring to the drawings which form part of this specification Fig. 1 is a diagramamtic view illustrating an application of the invention to a refrigerating system or installation of the compression type. The known or existing parts of the plan are indicated by relatively thin lines.

Fig. 2 is a diagrammatic view illustrating a mode of applying the invention to a refrigerating system of the absorption type. The known or existing parts of the installation are indicated by relatively thin lines and the parts according to the invention by relatively thick lines.

Fig. 3 is a longitudinal section of a preferred rotary auxiliary compressor employed in accordance with the invention.

Fig. 4 is a cross section of the auxiliary compressor seen in Fig. 3.

Fig. 5 is an enlarged detail view of portion of the auxiliary compressor seen in Figs. 3 and 4.

The invention may be applied to a compression type refrigerating plant which, as indicated in Fig. 1 includes a reciprocating compressor 2, a main discharge pipe 3, a condenser 4, a condensed liquid pipe 6, one or more cooling or expansion coils 7 for each of which an expansion valve 8 is provided to control communication between the coil and the liquid pipe 6. Each expansion coil 7 communicates at its other end with a. main suction or return pipe 9, through which the y vaporized cooling agent passes on its Way to the compressor 2. The above parts may be of any suitable construction and arranged and interconnected in any suitable manner. The plant may also include the usual oil and scale separators, an equalizer, a brine tank and various control and indicator devices, such parts being, however, omitted from the drawing for convenience of illustration.

In accordance with this invention a booster or auxiliary compressor 11 may be disposed in any convenient position and adapted to-be driven at the required speed.- An auxiliary suction pipe 12, leads from an inlet port 13 (Fig. 4) of the auxiliary compressor, whilst an auxiliary discharge pipe 14 (Fig. 1) may lead from a header 16, having branches 17,

Cir

which communicate with outlet ports 18 (Figs. 4 and 5) of the auxiliary compressor 11, the latter being of the rotary type as previously mentioned.

lf it is desired to extend the retrigerating effect of the plant, so that a larger amount of work vmay be carried out at the normal temperature or to lower the reitrigerating temperature throughout ythe system, the outer ends of the auxiliary suction and discharge pipes 12 and 14 may be connected, as at 12a and 14a to the main suction pipe 9 at different points thereof, and a by-pass valve 19 interposed in said pipe 9. between its points of connection with the auxiliary pipes, as indicated by the thick unbroken lines in Fig. 1. By appropriate manipulation of said valve 19 direct communication between the main suction pipe 9 and the main compressor 2, may be cut olf so that the gases from the expansion coils 7, instead of following their normal course, are diverted through lthe auxiliary suction pipe 12 into the auxiliary compressor 11 and pass therefrom through the auxiliary discharge pipe 14 into the main compressor 2. The path followed by the expanded gases, when the auxiliarycompressor is connected in the system vto operate in the manner previously described, is. indicated by unbroken arrows in Fig. 1.

' It will be evident that the additional suction to which the gases in the expansion coil or coils 7, may be subjected, by means of the auxiliary compressor 11, increases the refrigerating capacity of the plant and thus permits a greater output at the normal refrigerating temperature, or alternatively allows the plant to operate at a lower refrigerating temperature.

The auxiliary or by-pass circuit formed by the auxiliary pipes 12 and 14 and the auxiliary compressor'll, may be cut out by operating the by-pass valve 19 to thereby allow direct passage of gases through the main suction pipe 9, when it is desired that the plant should operate under normal conditions. Instead of connecting the auxiliary pipes 12 and 14 directly to the main suction pipe 9, as aforesaid, they may, if desired, be connected to the by-pass valve 19 which may be of any suitable internal construction.

If it is desired to lower'the refrigerating temperature obtaining in any particular expansion coil or coils as 7a. the outer ends of the auxiliary suction and discharge pipes may be connected, as at 12b and 14b directly to the particular expansion coil at points adjacent the outerend thereof, and a by-pass valve 19b interposed in the outer end portion of the coil 7a, between the points of connection of said auxiliary pipes and said coil, as shown in Fig. 1. In this case the gases from the-expansion coil 7a flow directly through the auxiliary suction pipe 12b into the auxiliary compressor 11 from which they are discharged by way of the auxiliary'discharge pipe 14b into the main suction pipe 9 and thence drawn into the main compressor 2, as indicated by the broken line arrows. rlhe increased suction thus obtaining in the expansion coil 7ZL lowers the temperature of that coil but does not in any way afect the normal refrigerating temperature of the other coils 7, from which the gases are induced along the main suction pipe 9 into the main compressor 2 in the usual manner. It will be evident that any of the expansion coils 7 may be operatively connected to, or placed into circuit with the auxiliary compressor 11in the manner indicated, so that the gases are, on their Way to the main compressor, b'y-passed through the auxiliary compressor 11 to thereby increase the suction and refrigerating effects of the respective coil or coils.

Referring now to Fig. 2 which indicates the application of the invention to a refrigerating system of the absorption type, the nul meral 3 is employed to denote a main discharge pipe through which the cooling agent passes from a generator 31 to a condenser 4. The arrangement of the liquid supply pipe 6, expansion coils 7, and expansion valves 8, may be similar to that referred to in the compression type system, but the return pipe 9 of the absorption system communicates with an absorber 32. A pump indicated at 33 may be provided as usual to pump the relatively strong liquor from the absorber 32 by way of an exchanger or intercooler 34 into thegenerator 31, whilst piping 36 may be provided to conduct weak liquor from the generator to the absorber 32. The aforesaid parts maybe arranged and connected in any suitable manner and other parts, such for example as an analyzer, rectifier, brine cooler, and variousy control and indicator devices may be appropriately incorporated in the system.

According to the invention the booster or rotary compressor 11 may be operatively connected between the return pipe 9 or thevex# pansion coils 7, and the absorber 32 in a Y manner substantially similar to that described with reference to the compression type system. Accordingly, reference numerals, similar to those employed in Fig. 1 are utilized to indicate the auxiliary compressor 1l,

the auxiliary suction and discharge pipes and associated parts seen in Fig. 2. The operation of the booster or rotary compressor v11, seen in Fig. 2, is also substantially similar to'thatl previously described butl a briefv description thereoiwill follow.

When the by-pass valve 19 as indicatedv by unbroken lines in Fig. 2 is closed to thereturn pipe 9 the y aseous cooling agent in the expansion coils 7 is subjected to the suction produced by the booster or rotary compressor 11, whereby ,the temperatures obtaining in the coils 7 ma be umformly lowered below normal, or if esired a greater volume of reed or placed 43, through which the gas is suction pipe 12 to enable the auxiliar presser 11 is of in Figs. 3 to frigeration may be effected at the normal wrking temperature. The gases are diverted through the auxiliary suction pipe 12 into the booster orcompressor 11 and are` expelled therefrom by way of the auxiliary discharge pipe 14 into the absorber 32 as indicated by unbroken arrows. I

1n instances where the rotary compressor 11 1s directly connected to an expansion coil 7? (or coils) as indicated at the right hand side of-Fig. 2 the degree of suction obtaining within such coil and the resultant refrigeratmg eti'ect may be increased without aecting the temperature of the other coil or coils. The path which the gases follow from an expansion coil 7 ya, which is operatively connecti in direct circuit with the auxiliary compressor 11, is indicated by broken arrows in F ig. 2.

1n all applications of the invention a stop valve 38 inay be inserted in the auxiliary compressor 11 to be positively cut out of the system'should it be desired to make repairs or adjustment to the auxiliary compressor. Such valve 38 may be shut, when the aforesaidby-pass valve 19 is open to the main suction orreturn pipe 9 to thereby prevent gases from passing through the auxiliaryvsuction pipe 12 into the rotary compressor 11.

As previously stated the auxiliary comthe rotary type and as seen 5 may include the usual cylindrical casing 41, in which a rotor 42 is eccentrically mounted, the casing being provided with an inlet or suction port 13 for the low pressure gas and one Aor a series of outlet ports 18, controlled by suitable valve means forced at relatively high pressure by way of branches or nipples 17 into a header 16 to which the aforesaid auxiliary discharge pipe 14 is connecthifrh temperature gas in ed. 'llhe rotor 42 may carry the influenced Vanes 44 which contact with the inner surface of the casing 41.

1n order to prevent the g the discharge space 46 at one side of the rotor vanes 44 from leaking or escaping into the low pressure or suction space 47 at the other side of the rotor vanes, the casing 41, is preferably provlded in accordance with 0the invention with a recess 48 which ext-ends lon itudinally of the casing 41 in its inner surface adjacent the outlet ports 18 and between the latter and the inlet port 13 and is adapted to accommodate a sealing strip- 49. Extending from said recess 48 is one ora series of pockets or chambers 51 each of which is closed by a screw plug 52 or the like, and is placed into communication with the discharge or high pressure space 46 at one side of the rotor vanes 44, for example by means of an orifice or oriices 53 formed through the said sealing strip 49 Whose inner surface may be cambered or bevelled as seen usual spring` high pressure and in Fig. 5. IThe gas at high pressure being admitted into the said pockets or chambers 51 forces the sealing strip 49 tightly into contact with the outer periphery of the rotor 42 and the outer ends of the rotor vanes 44, as they arrive in alignment with the strip. The discharge or high pressure space 46 is thus effectively isolated from the suction or low pressure space 47. A spring 54 may be located in each pocket or chamber 51 between the screw plug 52 and the outer face of the sealing strip 49 to ensure that the latter is forced into leak proof contact with the rotor 41 and its vvaries 44. The pressure exerted by the spring 54 may be adjusted as desired by means of the screw plug 52 which may have a lock nut 56 associated therewith.

1t will be appreciated that the cost of a rotary compressor which is employed as an auxiliary to reduce the normal suction pressure in accordance with the invention, is considerably less than the cost of a corresponding reciprocating compressor of the type usually employed in refrigerating systems, and whilst rotary compressors are not ordinarily regarded as suitable for such work and owing to their relatively lower suctionl capacity would not be capable of'satisfactorily supplanting or working independentlyof the reciprocating compressor in such installa-.

. ters Patentis 1. A refrigerating system comprising means for taking up refrigerant vapor and putting it under higher pressure, a condenser connected with said means, a high pressure conduit leading from the condenser, a return low pressure conduit leading back to said means, a plurality of expansion coils connected in parallel With said conduits, and av circuit including a compressor and an'auxiliary suction pipe and an auxiliary discharge pipe connecting said compressor with the main return pipe which leads from the expansion coil or coils to the rst-mentioned means whereby the refrigerant vapor upon leaving said expansion coil may be caused to pass through said auxiliary -pipe circuit said means. p

2. A refrigerating system comprising means for taking up refrigerant vapor and putting it under higher pressure, a condenser connected with said'means, a high pressure conduit leading from the condenser, a return low pressure conduit leading back to said means, a plurality of expansion coils connected in parallel with said conduits, and a valve-controlled auxiliary before returning to y valve-controlled auxiliary circuit including i. Y iyrioeoo in the main return pipe between .the last-- a compressor, auxiliary suction and discharge mentioned ends of the auxiliary suction and pipes respectively connected at their one ends to the suction and discharge spaces of said compressor and at their other ends to said inain return pipe, and a ley-pass valve arranged to divert the vreirigerarrt vapor through said auxiliary suction and discharge pipes, when said compressor is operating for the purpose specied.,

8. A rctrigerating isystem comprising means for taking up refrigerant vapor and putting it under higher pressure, a condenser connected with said means, a high pressure conduit leading from the condenser, a return low pressure conduit leading back to said means, a plurality ot expansion coils connected in parallel with said conduits, and a valve-controlled auxiliary circuit including a compressor having an inlet port leading to a suction chamber and an outlet port leading troni a discharge chamber thereof, auxiliary suction and discharge pipes connected at their one ends to said inlet and outlet ports respectively and at their other ends to said main return pipe, and a by-pass valve located return pipes.

A refrigerating system comprising ineans for taking up refrigerant vapor and putting it underuhigher pressure, a condenser connected with said means, a high pressure conduit leading from the condenser, a return low pressure conduit leading back to said means, a plurality or expansion coilsA connected in parallel with said conduits, and a Valve-controlled auxiliary circuit including a compressor, auxiliary suction and discharge pipes extending between said suction or compressor and said main suction or return pipe 'to thereby provide for said refrigerant Vapor an auxiliary circuit which leads from said main return pipe through the auxiliary suction pipe, the compressor and the auxiliary discharge pipe back to said main return pipe,

and valve meanstor controlling the passage` ol3 the vapor through said main return pipe and said auxiliary suction and discharge pipes, for the purpose s peciiied lin testimony Whereol2 l aiifix my signature.

WlLLAll/ DUNKERLEY 

